Category Archives: Systems

Tips on Operating Systems mostly focus on Linux and Mac OS X
Trucs et astuces, tests autour des systèmes d’exploitation, principalement Linux et MacOsX

Why Docker sounds like a revolution ?

20140418-082531.jpgThese two last days, I was participating to devoxx in Paris. One of the star topic of the event this year was Docker so I attempt different talk about this container technology I already has discovered in a previous JUG session. It was not an evidence that this technology was more than something interesting for DEV needing small, fast starting, small memory footprint, environment for testing. With my OPS hat, I did not catch the interest. This was before Devoxx and the different talk. The aspects I’ll detailed in this post have not been addressed during Devoxx, as much as I have seen, as mostly the DEV aspects have been addressed, I going to synthesize my opinion.

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AIX network debugging

Since a couple of day at work I had to investigate on some network issues for an application, it seems that we have a strange ARP configuration that may be the main issue… by the way, I discovered another strange thing where icmp packets sent in burst mode (like a flood) are lost at variable rates. Here is the note on my investigations

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Problem with nvidia raid and grub2

It’s not the first time I have some trouble to setup grub2 correctly with my nvidia raid system (also called fake-raid) … I did not find exactly why, but for sure i never try to install grub2 correctly from yast or in manual mode.

The first solution to find was : how to boot a fresh installed system when the bootloader has not been configured. The solution is here : This tool is really simple and so efficient to boot !  I recommend to have this in your linux emergency kit !

The second solution, once the system has start is to reinstall a bootloader. Here, in fact the solution is easy : destroy this f**** grub2 and replace it by the legacy really good grub ! lol

Then it works … last step to me: understand why gnome is taking so long to start ?!? or the answer is in the question …

I love Linux !

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Quickly create word list

An easy way to create a word list in bash :

for i in {a..z} ; do echo $i ; done
for i in {a..z}{{a..z},{0..9},-} ; do echo $i ; done
for i in {a..z}{{a..z},{0..9},-}{{a..z},{0..9},-} ; do echo $i ; done

The first line creates a list of one characters word from a to z

The second line creates a list of two characters word from aa to z- the alphabet for the second character can be a-z or 0-9 or –

The third line is a three character word list.



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Raspberry PI – wan emulation

PIWan project : Here is a new, quick & dirty project to be done with a raspberry PI : At work we currently have to simulate our application for a worldwide usage. We have really great tools for that but they need expertise and specific campaigns. The purpose of this document is to describe a RPI based solution with two Ethernet cards and some clever command lines to simulate a wan network for developers. The advantage of this solution will be to cost less than 100euros and will be easy to use with the right documentation.

See next pages for implementation details:

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BeagleBone Black – configure NTP client

The BeagleBone black do not have Real Time Clock and as a consequence each time you reboot, you’re back at time 0. To get it updated to the local hour, you can configure NTP client (if connected to network) using the following commands:

root@beaglebone:~# opkg update
root@beaglebone:~# opkg install ntp ntpdate
root@beaglebone:~# mv /etc/localtime /etc/localtime.old
root@beaglebone:~# ln -s /usr/share/zoneinfo/Europe/Paris /etc/localtime
root@beaglebone:~# killall -KILL ntpd
root@beaglebone:~# ntpdate
root@beaglebone:~# /etc/init.d/ntpd start
root@beaglebone:~# date
Sun Jun  2 17:41:10 CEST 2013
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PirateBox upgrade to Forban

I’m looking to upgrade my two pirate box to test the mesh network forban between the two. Apparently, this will slow down the device as the TP Link small devices are not so powerful, but i like the idea to be able to create mesh network between piratebox. In my point of view it is the right way to make this project real.

I actually have my two piratebox configured in version 0.5, i’ll firstly update them to the latest version, then add the Forban tool following Matthias’s materials.

I’ll upgrade my TP Link Mr3020 and TP Link MR3040.

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